On October 19, 2026, U.S. District Judge Debra M. Brown allowed the United States to intervene in the NAACP’s Clean Air Act suit against X.AI Corp. and MZX Tech LLC on behalf of the EPA Administrator, but denied the government’s request to dismiss the case. The order addressed the government’s role in the lawsuit, not the merits of the pollution allegations.

Why intervention did not mean dismissal

The Clean Air Act gives the EPA Administrator an unconditional right to intervene in a citizen suit, and the court allowed the United States to join on the Administrator’s behalf. But joining a case did not give the government authority to end another plaintiff’s lawsuit unilaterally.

Judge Brown found that Federal Rule of Civil Procedure 41 addresses a plaintiff dismissing its own action. She also found no authority in the Clean Air Act for the government to dismiss the plaintiffs’ suit over their objection. The court rejected the government’s constitutional-avoidance argument as well, finding no statutory ambiguity that supported an implied dismissal power.

The plaintiffs are the NAACP and the Mississippi State Conference of the NAACP. The court’s order did not decide whether X.AI Corp. or MZX Tech LLC violated environmental law.

What the lawsuit alleges and seeks

The complaint alleges that X.AI Corp. and MZX Tech LLC built and operate the Colossus Gas Plant in Southaven, Mississippi, without required permits, in violation of the federal Clean Air Act and Mississippi’s State Implementation Plan.

The plaintiffs seek an injunction requiring lawful operation, installation and operation of the best available control technology, and civil penalties of up to $124,426 per day per violation. They also seek costs and attorneys’ fees. These are requested remedies in the lawsuit.

The order’s filing deadline

The court directed the United States to file a pleading meeting Federal Rule of Civil Procedure 24(c)’s requirements by October 23, 2026, if it intended to participate. If that pleading required a response, the order set October 30 as the response deadline.